Warp

The Data Cube Tool has a warp button, new with version Lx43.

Notes (as of version Lx43):

The Outliers button has been removed. Functions to clip outliers
(pixels out of range) are in the cube button.

The warp button allows one image to be warped into another by using
tie points. As of Lx43, the warp functions are bi-linear, quadratic,
cubic, etc. Once the tie points are recoreded, a folder of images
can be warped using them, via either the warp button
or the Process Folder Tool.

Warp Menu

Please use the control key to get
documentation on these functions.

Collect tie points - ON, starts a loop during which you can view
one image or the other using the shift key, and click
on tie points that connect matching features in both. The control
key stops this loop. The warp button turns PINK
when the loop is running. The tie points are collected in a list
in memory

Upon stopping the collection loop, the tie points are listed in a text
window. To save this as a tie point file, use File
/ save TEXT.

The shorthand notation using slashes (as
above) is explained here,
as well as here.

How to 'unwarp' a series of images.

Collecting Tie Points

Load a series of images into the Data Cube
Tool, using Read / as image files. The
cube must contain at least two images, which are the 'clean' (not warped)
image and the warped image.

Select the cube with the cube! button.

Select the clean image with the ref slc! button, and the
warped image with the flick slc! button.

Turn on the tie point collection loop with Warp / collect
tie points - ON. Collect as many tie points as you need.

Use the shift key to shift from the clean image to the warped one.

Select a feature that appears in both images. Click on it in the
clean image, then, shift-click on it in the warped image.

When you click on the clean image, a small circle appears over the
feature.

Then, on shift clicking on the same feature in the warped image,
a number will replace the small circle, and a line will run from the
number to the clicked position in the warped image.

The number is the index when the tie points are listed.

This process may be halted (with the control key) and
restarted later. Only immediately after restarting, you may have
to hit the shift key to get the image to display properly.

Tie points may be deleted using warp / delet tie points,
while the loop is running. The remaining tie points will be renumbered.

When the loop is halted with the control key, the tie points
are listed in a text file. This file is not saved automatically.
When the list is finished, save this text window to a file using File
/ save TEXT (in the Lispix menu
bar.)

This tie point file is loaded at a later time using warp / load
tie points.

Unwarping Images

Open a data cube with at least one image which you want to unwarp.
This image must be the same size as the images from which the tie points were
collected.

Select the cube in the Data Cube Tool with the Cube!
button.

Load the tie points: warp / Load tie points.

Make the x and y warp maps: warp / Make warp shift maps.
These images must be there when any images are unwarped. They
can be saved as files and loaded later, but it is just as fast to make them
directly from the tie point file.

Unwarp an image using warp / unwarp image, or a folder
of images using warp / unwarp folder.

A folder of images can also be unwarped using the Process
Folder Tool, and its warp
command. The warp maps need to be open when this is done, but no
data cube need be open.